1987 suburban heater core w/A.C. removal and replacement help.

[Redgriz]

I am trying to replace the heater core. it is leaking. I have followed the Chilton's but I am stuck with three type pins that I cannot seem to remove. I have read that some have taken off the fender well to get at them. Is there a tool for these or do they have a nut on them through the firewall. glove box is out, removed computer can see everything inside but can't seem to find the place to remove the aforementioned screws.. Any suggestions or tips would be greatly appreciated.

[idmetro]

Redgriz;

I changed the heater core on my 86 recently and I can tell you that you REALLY need to drop the inner fender well to access the nuts on the bottom on the engine side of the heater housing (under the fan attachment area). I pulled the right front tire and fenderwell which allowed me room to work.

Those nuts have to come off to be able to remove the inside portion of the heater housing (they are blind on the inside and hold the housing to the firewall). Once the nuts are off you will be able to remove the heater case from the inside; just leave the half in the engine compartment in place.

In my case once I got all of the nuts off on the engine side (top and bottom; look carefully two of mine were buried in the sealant goo that I had to chip off before I could unscrew them) The case still seemed stuck until I used a hammer handle to push the studs back into the cab (later I found they had spring clips threaded down onto them under the engine side of the housing (against the firewall); no doubt to make assembly easier).

Before you unhook everything label the vacuum lines that hook to the actuators (You will need to get them hooked back up correctly for the heater controls to work properly).

Once you get the housing out you will need to split that case to access the heater core. There are a couple of nuts buried deeply under the foam gasket where the core mates to the firewall. Also I found you have to remove the control rod that passes through one of the air deflectors (black plastic one, rectangular in shape) to be able to split the case as the control rod pins the two halves of the case together. Be sure to support the bottom ear of the deflector when you go to pull the control rod or you will break off the ear and have to reglue it (jb weld seems to work fine).

Also when you go the reconnect make sure you get the vacuum lines on before you bolt the housing back into place; the one on the backside is all but impossible to do otherwise.

Don't despair its not as bad as it sounds and once you get the heater housing out you can take it inside where it will be much easier to clean out the years of accumulated crud as well as giving the deflector plastic a chance to heat up so you will be less likely to break it.

As the manual says assembly is the reverse of removal. Once you are all back together you can bask in the warmth!

Good Luck.

[rdh2]

Originally Posted by Redgriz

I am trying to replace the heater core. it is leaking. I have followed the Chilton's but I am stuck with three type pins that I cannot seem to remove. I have read that some have taken off the fender well to get at them. Is there a tool for these or do they have a nut on them through the firewall. glove box is out, removed computer can see everything inside but can't seem to find the place to remove the aforementioned screws.. Any suggestions or tips would be greatly appreciated.

Just my $.02--- On my '85 I did not remove the fender well as I was able to access the nuts on the engine side of the firewall with a long extension and swivel socket. I did find it easier to pull the dash pad for access to the ducts from the top. The whole job took about 3 hours and I didn't rush it. As I recall, the nuts are located: 1 at the top, 1 below blower motor area, and 1 to the inside of the A/C evaporator (towards exhaust manifold).